Conventionally, as a drive unit, an interlocking chain type lifting apparatus has been known that moves a workpiece such as a heavy material by using a pair of lifting interlocking chains interlocked with each other and integrally moved vertically (for example, refer to Patent Document 1).
The pair of lifting interlocking chains used in this conventional interlocking chain type lifting apparatus is designed to be driven by a pair of lifting sprockets, which are arranged to face the pair of lifting interlocking chains, respectively.